An optimized Linear Lorentz-force Actuator for biorobotics and needle-free injection

Abstract

Voice coils are a configuration of Linear Lorentz-force Actuator (LLA) that offer efficient transduction of electrical energy into linear motion. The simple geometry of a typical voice coil motor makes the configuration easily tunable for custom applications. Recent advances in high-energy magnets offer significant advantages in LLA performance when properly tuned. This thesis outlines the design, construction, and implementation of an optimized LLA which achieves superior performance to any commercially available linear motor of its size and mass. The actuator weighs 580 g, and produces 50 N continuously at 10 Hz through its 30 mm travel. It features integrated feedback control circuitry, making it a standalone modular system which lacks only a power source. The use of this LLA benefits many applications, including biorobotic actuation and needle-free injection. Using this LLA as an actuator for a biorobotic fish fin, higher precision motion is achieved at higher bandwidth than off the shelf alternatives. In two different needle-free injection systems, full control of injection pressure over time is enabled in a more compact package than previously possible. Finally, the LLA is implemented to drive a portable rapid-fire needle free injection device capable of delivering 2 mL/s at a 2 MPa.